1. Field of the Invention
The present invention relates in general to an iontophoretic device for the administration of an electric current to a soft tissue of a patient, more specifically to an iontophoretic device that is capable of continuous, highly directed application of an electric current to the soft tissue of a patient.
2. Background Art
Iontophoresis is a technique which can be used to transport soluble ions across a body surface or membrane. This technique is based on the principle that an applied electric potential will cause ions to move in a desired manner according to the charge of the ions, the size of the ions, the magnitude of the electrical current or voltage being applied, electrode composition, and duration of the electrical current or voltage. Iontophoresis is an example of a method more generally known as electrotransport, which has been found to be very useful in the transdermal administration of medicine and also in some diagnostic applications.
Iontophoresis has been used to administer medicament to soft tissues of patients, including to the eyes of patients. Such treatments have been successful due to the increased ability of medicine to penetrate the tissue of the patient, and treat the selected area. However, care must be taken in utilizing iontophoresis for the treatment of these soft tissue areas. The application of an electric current to drive a medicament iontophoretically can have the tendency to bum the area of application if too much electric charge is allowed to pass at too great a rate. Therefore, care must be taken in the amount of electric charge applied over a period of time.
An additional concern in the use of iontophoresis for the treatment of soft tissues is that the application of the electric current to the tissue may treat healthy as well as targeted areas. It has been know in the art to limit the application area of the electric current in order to minimize this effect. Such devices have been formed in portions of an annulus, a complete annulus, or a reduced-size applicator. However, none of these solutions have addressed the need for specific application of electric current to a definite area.
One solution that has addressed the application of electric current to a specified area is the application of medicament utilizing a thin tube filled with the medicament whose end is placed manually on the area to be treated, and manually held in position until treatment is completed. While this solution addresses the need for highly specified application of electric current, such a solution is difficult to administer. Since the tube filled with medicament is held manually, any movement, regardless of magnitude, by the administrator or the patient, may alter or even completely change the area of application.
Therefore, it is an object of this invention to provide for the highly directed application of electric current to a soft tissue of a patient, such as an eye, using iontophoresis.
It is a further object of this invention to insure consistent and constant contact of the electric current to the specified area, without the use of unreliable manual means.
The invention comprises a high current density iontophoretic device, comprising a reservoir, an applicator, means for substantially maintaining orientation of the device and means for iontophoretically administering the medicament from the reservoir. The reservoir is capable of retaining medicament. The applicator is positionable upon a surface of an eye and includes at least one punctation therethrough. The at least one punctation is capable of being placed in fluid communication with each of the reservoir and at least one treatment area of an eye upon operative positioning thereof. The orientation maintaining means maintains the applicator in the desired orientation upon operative positioning thereof. The iontophoretic administering means serves to administer a medicament from the reservoir to the at least one punctation and, in turn, to an eye of a patient.
In a preferred embodiment, the reservoir and the applicator comprise a single unitized member. In other preferred embodiments, the reservoir and the applicator are separate members, and the device further includes a conduit in fluid communication with both the reservoir and the at least one punctation to, in turn, facilitate the remote positioning of the reservoir relative to the applicator. In such embodiments, the conduit is of a substantially circular cross section, and is formed from a flexible material.
In another preferred embodiment, the applicator includes a contact surface and the orientation maintaining means comprising a releasable retaining material associated with the contact surface. In certain embodiments, the releasable retaining material comprises an adhesive. In other embodiments, the releasable retaining material comprises a lightly crosslinked polymer having a tacky surface configuration.
In a preferred embodiment, the device further comprises means for substantially sealing the at least one punctation relative to at least one treatment area. This serves to substantially preclude undesired migration of electric current away from the at least one treatment area. In one such embodiment, the sealing means comprises a raised barrier, associated with the applicator, and at least partially surrounding the at least one punctation. In this embodiment, the applicator comprises a convex shape, to ensure secure contact between the raised barrier and the area surrounding the at least one punctation.
In a preferred embodiment, the at least one punctation is formed in a variety of geometric shapes. Preferably, the shape thereof comprises a circular geometric configuration. It is preferred that the circular geometric configuration includes a diameter of less than 2 mm.
In another preferred embodiment, the applicator is shaped to substantially correspond to the shape of a soft tissue of a patient. In yet another preferred embodiment, the reservoir includes one of a medicament and a medicament carrier, which may comprise a hydrogel medicament carrier.
The invention further comprises a method for treating the eye of a patient comprising the steps of: (a) providing a high current density iontophoretic device; (b) positioning an applicator of the high current density iontophoretic device on the eye of a patient; (c) positioning at least one punctation of the applicator over the portion of the eye requiring treatment; and (d) iontophoretically driving a medicament through the at least one punctation of the applicator of the high current density iontophoretic device.
In a preferred embodiment, the method further comprises the step of retaining the at least one punctation in the desired orientation upon the positioning thereof. In another preferred embodiment, the method further comprises the step of sealing the at least one punctation relative to the surface of the eye, to, in turn, preclude migration of electric current.